Hybrid Car – More Fun with Less Gas

Solar Heater Success! - Page 2

register ::  Login Password  :: Lost Password?
Posted by Bill Kreamer on October 11, 2005, 7:52 pm
 
My comments are interspersed below.





Yes, given a nice, unrestricted air flow. For instance:

    -don't use a serpentine flow path. Parallel is better than series.

    -do use a diagonal mounting for the felt; supply intake to the front
side,

       remove hot air from the back.

You can get a better picture by emailing me (kreamer@adelphia.net) for a
.pdf file of suggested plans.




Properties of textile fibers for low and medium temperatures, from

http://vme.net/bluesky/site/faqtemp.html  :



Fiber Name, Recommended continuous operation temp (dry heat)


Polyester (Dacron), 270F - 132C
Acrylic Copolymer (Orlon), 248F - 120C
Homopolymer Acrylic (Dacron T) 284F - 140C



Foil-faced foam insulation, plastic glazing and other collector materials
will suffer as much as polyester felt. If you stagnate the collector,
melting is theoretically possible, but some degrading is most probable. So,
homebuilt air heating collectors should never be allowed to stagnate. Even
fan-driven collectors need to thermosyphon well so they can deal with the
odd power outage. It's risky to install ducting with homebuilt air heating
collectors because that stifles thermosyphoning. A vertical collector
installation makes for some self-limiting in spring and fall, and may let
you get away with using plexiglas/acrylic glazing. In the summer, a good
thing to do is cover or remove the collector.



-Bill








Posted by redbelly98 on October 11, 2005, 2:13 pm
 
This is neat, it sounds a lot like something my neighbor and I built
last spring to heat one of the rooms in his house (it tends to be
cooler in that room than the rest of his home).

I have just a couple of comments.  First, I would keep an eye on the
plexiglass, since it can soften and sag at high temperatures.  May be
not a problem on cold days, when you would actually use the heater, but
repeated heating on warm days will most likely make it sag over time.
My friend also used plexiglass.  We didn't see any buckling the two
times we tested it, but it did appear to have sagged a little in just a
few hours of use.

FYI, we used clamps to hold the plexiglass in place.  Also had foam
weather-stripping between the plexiglass and the frame.

There's a way to measure higher temperatures, but you need to be
somewhat familiar with electronics.  You'll need an ohm-meter, and to
purchase a thermistor (cost is a few dollars at Radio Shack, their part
# 271-110A).   You just measure the resistance of the thermistor (which
is inside your heater, or wherever you want to measure temperature).
Then read from a chart (provided on the back of the package) to convert
the ohm-meter reading into a temperature.  I've measured 200 F using
these (not on a solar heater, but for a different project).  The
thermistor is pretty small, about a 1/8" in size with two half-inch
long wires sticking out.

Good luck!

Mark


This Thread
Bookmark this thread:
 
 
 
 
 
 
  •  
  • Subject
  • Author
  • Date
please rate this thread